Washington, Apr 2: The bacteria in the human gastrointestinal tract, known as gut microbiota, may play a key role in regulating weight, according to a new study.

Gut microbiota, the trillions of bacteria that populate the human gastrointestinal tract, perform a variety of chores.

These “friendly” microbes help extract calories from what we eat, help store these calories for later use, and provide energy and nutrients for the production of new bacteria to continue this work.

According to John DiBaise, M. D., a Mayo Clinic Arizona gastroenterologist and lead author of the study, several animal studies suggest that gut microbiota are involved in regulating weight and that modifying these bacteria could one day be a treatment option for obesity.

One study cited by the authors observed that young, conventionally reared mice have a significantly higher body fat content than a laboratory-bred, germ-free strain of mice that lack these bacteria, even though they consumed less food than their germ-free counterparts.

When the same research group transplanted gut microbiota from normal mice into germ-free mice, the germ-free mice experienced a 60 percent increase in body fat within two weeks, without any increase in food consumption or obvious differences in energy expenditure.

Another animal study reviewed by the authors focused on the gene content of the gut microbiota in mice. Finding more end products of fermentation and fewer calories in the feces of obese mice led researchers to speculate that the gut microbiota in the obese mice help extract additional calories from ingested food.

“These results suggest that differences exist in the gut microbiota of obese versus lean mice, raising the possibility that the manipulation of gut microbiota could be a useful strategy for regulating energy balance in obese people,” said DiBaise.

“In particular, it is essential to demonstrate unequivocally whether differences in gut microbiota in obese versus lean people are the cause or the result of obesity,” says Dr. DiBaise.